Non-aqueous secondary batteries (hereinafter, also referred to simply as “secondary batteries”) such as lithium ion secondary batteries have characteristics such as compact size, light weight, high energy-density, and the ability to be repeatedly charged and discharged, and are used in a wide variety of applications. A non-aqueous secondary battery generally includes battery components such as electrodes (positive electrode and negative electrode) and a separator that isolates the positive electrode and the negative electrode from one another and prevents short circuiting between the positive electrode and the negative electrode.
In recent years, battery components including functional layers, such as an adhesive layer provided in order to improve adhesiveness between battery components, have been used in secondary batteries. Specific examples of such battery components that have been used include an electrode that is obtained by further forming a functional layer on an electrode substrate formed by providing an electrode mixed material layer on a current collector and a separator that is obtained by forming a functional layer on a separator substrate (for example, refer to PTL 1).
Specifically, PTL 1 proposes a separator for a secondary battery that is obtained by forming a porous membrane containing non-conductive particles and a binder as a layer on a separator substrate and further forming an adhesive layer containing a specific particulate polymer on the porous membrane layer. PTL 1 reports that through use of this separator including the adhesive layer, favorable adhesion between the separator and an electrode can be achieved through the adhesive layer and battery characteristics of a secondary battery can be improved.